Ashley ate 5 slices of pizza. Tiffany ate 2 slices. If Ashley ate $\dfrac{5}{10}$ of the pizza, what fraction of the pizza is remaining?
Solution: If 5 slices represent $\dfrac{5}{10}$ of the pizza, there must have been a total of 10 slices. $\text{fraction of pizza remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 7 slices, which leaves 3 out of 10 slices remaining. There is $\dfrac{3}{10}$ of the pizza remaining.